Japanese Patent Laying-Open No. 2002-218793 discloses a power output apparatus incorporated in hybrid vehicles and electric vehicles with a motor generator as the power source. The power output apparatus includes a 2Y motor having two 3-phase coils wound around the same stator or two motor generators, two inverters corresponding to the 2Y motor or two motor generators, respectively, and a DC (direct current) power supply connected between the neutral points of the 2Y motor or two motor generators. In accordance with this power output apparatus, the inverter input voltage can be adjusted within a wide range by setting the potential difference between the neutral points of the 2Y motor or two motor generators smaller or larger than the voltage of the DC power supply under control of the two inverters.
There is the conventional approach of using a hybrid vehicle or electric vehicle as the AC power supply employing the power output apparatus incorporated in the hybrid vehicle or the like. Specifically, this approach is directed to using the hybrid vehicle or the like as the backup electric power source in the case of emergency and disaster or as the commercial power supply when commercial power supply facilities are not available in the neighborhood such as at camps. Such usage methods will increase the commercial value of the hybrid vehicle and the like.
Japanese Patent Laying-Open No. 2002-374604 discloses the approach of allowing an AC output of 100V from a vehicle that is mounted with a secondary battery. The vehicle includes a secondary battery, a dedicated AC100 V inverter to provide an AC output of 100 V using the power from the secondary battery. The limitation of an AC100 V output is allowed based on the SOC (State of Charge) of the secondary battery and other states of the system. Since the driving motor can be controlled favorably using power from the secondary battery by the limitation of the AC100 V output in accordance with this vehicle, favorable driving control of the vehicle can be ensured, and an AC output of 100 V can be provided using the power from the secondary battery.
Although it is desirable to use a hybrid vehicle or the like as an AC power supply, as set forth above, the power output apparatus disclosed in Japanese Patent Laying-Open No. 2002-218793 cannot generate and provide to an external source an AC power.
Although the vehicle disclosed in Japanese Patent Laying-Open No. 2002-374604 is advantageous in that an output of AC100 V can be provided to an external source and favorable driving control for the vehicle can be ensured, no measures are taken from the standpoint of efficient voltage utilization to obtain the maximum AC power. This vehicle is disadvantageous in that a dedicated inverter for AC100 V output is required, leading to the possibility that reduction in size, weight, and cost of the vehicle may be prevented.